Respiratory and metabolic effects of massive administration of isotonic saline solution in heaves-affected and control horses.
Authors: Jean D, Vrins A, Lavoie J P
Journal: Equine veterinary journal
Summary
# Editorial Summary: Rapid Saline Administration in Heaves Whether rapid intravenous saline infusion might relieve airway obstruction in equine heaves (recurrent airway obstruction) remains unclear despite anecdotal clinical use, prompting investigators to rigorously evaluate both efficacy and safety in affected and control horses. Five healthy controls and nine heaves-affected horses received 30 litres of isotonic saline administered intravenously, with pulmonary function testing, arterial blood gas analysis, and serum electrolyte monitoring performed at multiple timepoints over 10 days. Contrary to the proposed therapeutic benefit, heaves-affected horses showed significantly increased pulmonary resistance at 180 minutes post-infusion compared to baseline, whilst control horses similarly demonstrated transient decrements in lung function—decreased arterial oxygen tension at 90 minutes and increased airway resistance at 180 minutes. Notably, heaves-affected horses did present with baseline metabolic alkalosis and hypochloraemia that resolved following saline administration, though this electrolyte correction produced no clinical airway improvement and side effects resolved within six hours. For practitioners considering rapid saline as adjunctive therapy for acute heaves crises, this evidence suggests the treatment offers no meaningful bronchodilation and transiently worsens pulmonary mechanics in both affected and healthy horses, making it unsuitable as a standalone or primary intervention for managing airway obstruction.
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Practical Takeaways
- •Do not rely on rapid saline infusion as a treatment for heaves; this study shows it does not improve airway function and may transiently worsen it
- •If saline is administered to heaves-affected horses for other reasons, expect temporary worsening of pulmonary function around 3 hours post-infusion, which resolves within hours
- •Heaves-affected horses may have pre-existing metabolic alkalosis and electrolyte imbalances; saline corrects these but does not address airway obstruction
Key Findings
- •Rapid isotonic saline administration produced no beneficial effects on lung function in heaves-affected horses during infusion
- •Both control and heaves-affected horses showed significantly increased pulmonary resistance at 180 minutes post-infusion, indicating transient lung function decrement
- •Heaves-affected horses had baseline metabolic alkalosis with hypochloraemia that resolved following saline administration and returned to baseline within 6 hours
- •Rapid isotonic saline administration alone is not an effective therapy for heaves in horses